The present invention relates to a grounding mechanism for electrostatic charge of a cassette player, etc. which is capable of preventing electrostatic charge on a user of the player from entering into an electric circuitry of the player.
FIGS. 1 and 2 show an example of a conventional mechanism of this type, in which reference numeral 1 depicts a panel mounted on a front end of a chassis 2 and an opening 3 is formed in a center front surface of the panel 1 through which a cassette A is inserted into or pulled out from the chassis 2. A flap 4 is provided in an inside of the opening 3. The flap 4 is hinged at an upper edge thereof by a support pin 5 and biased by a spring 6 so that the flap is normally held in a position in which the opening 3 is closed thereby, as shown in FIG. 1. A grounding plate 7 is provided along an inner lower surface of the panel 1 and has a top end in contact with a lower edge of the opening 3 and in contact with a lower edge of the flap 4 when it is in the closed position, A printed circuit board 8 mounting electronic components thereon and a cassette holder 9 are also provided in the chassis 1.
With such construction, when the cassette A is inserted into the opening 3 by pushing the flap 4 with a front end of the cassette A against the resiliency of the spring 6, electrostatic charge on the cassette A is grounded through the contact between the flap 4 and the grounding plate 7 instantaneously to thereby protect the electronic components on the printed circuit board 8 from electrostatic breakdown.
In such conventional system, however, the provision of the grounding plate 7 in contact with the inner surface of the panel 1 makes an overall structure of the cassette player complicated, resulting in an increased manufacturing cost.
Further, since electrostatic charge on the tape cassette is grounded during a very short time before a movement of the flap 4 to an open position is initiated by the contact thereof with the front end of the cassette, the charge on the cassette is not always grounded completely.